1. Field of the Invention
This invention relates to a novel synthesis of conjugated eicosadienoic acid (CEA). In one aspect, this invention relates to a novel synthesis of 11-cis, 13-trans eicosadienoic acid, also known as 11(Z),13(E)-eicosadienoic acid.
2. Background
Conjugated linoleic acid (CLA) is a general term used to name positional and geometric isomers of linoleic acid.
Conjugated eicosadienoic acid (CEA) is a general term used to name positional and geometric isomers of the C-20 fatty acid of 11-cis, 13-trans eicosadienoic acid, also known as 11(Z),13(E)-eicosadienoic acid.
Linoleic acid and eicosadienoic acid are straight chain carboxylic acids having double bonds between the ninth and tenth, twelfth and thirteenth carbons and eleventh and twelfth, fourteenth and fifteenth carbons, respectively. Linoleic acid is 9-cis, 12-cis octadecadienoic acid [9(Z),12(Z)-octadecadienoic acid]. The numbers are counted from the carboxylic acid moiety. See Formula (1) for 9-cis, 12-cis octadecadienoic acid [9(Z),12(Z)-octadecadienoic acid]. See Formula (2) for 11-cis, 13-trans eicosadienoic acid, [11(Z),13(E)-eicosadienoic acid]. ##STR1##
Conjugated linoleic acid (CLA) has two conjugated double bonds between the ninth and the twelfth carbons or between the tenth and thirteenth carbons, with possible cis and trans combinations. Conjugated eicosadienoic acid (CEA) has two conjugated double bonds between the eleventh and fourteenth or between the is twelfth and fifteenth carbons, with possible cis and trans combinations. Conjugated double bonds means two or more double bonds which alternate in an unsaturated compound as in 1,3 butadiene. The hydrogen atoms are on the same side of the molecule in the case of cis. The hydrogen atoms are on the opposite side of the molecule in the case of trans. See Formula (3) for conjugated linoleic acid (CLA). See Formula (4) for conjugated eicosadienoic acid (CEA). ##STR2##
The free, naturally occurring conjugated linoleic acids (CLA) have been previously isolated from fried meats and described as anticarcinogens by Y. L Ha, N K. Grimm and M. W. Pariza, in Carcinogenesis, Vol. 8, No. 12, pp. 1881-1887 (1987). Since then, they have been found in some processed cheese products (Y. L. Ha, N. K. Grimm and M. W. Pariza, in J. Agric. Food Chem., Vol. 37, No. 1, pp. 75-81 (1987)).
The free, naturally occurring conjugated eicosadienoic acids (CLA) are not known to exist.
Cook et al. in U.S. Pat. No. 5,554,646 disclose animal feeds containing CLA, or its non-toxic derivatives, e.g., such as the sodium and potassium salts of CLA, as an additive in combination with conventional animal feeds or human foods. CLA makes for leaner animal mass.